# Shared Flashcard Set

## Details

CA-Physical Science-Simple Machines
Work and Simple Machines
45
Science
11/08/2009

Term
 Machine
Definition
 A device that makes work easier
Term
 Direction or size
Definition
 Machines make work easier by changing the _______ or ______ of the force you exert
Term
 gravity and friction
Definition
 Machines try to overcome the forces of ___ and ___ that resists movement of objects
Term
 Effort force
Definition
 Force that is applied to a machine
Term
 Resistance force
Definition
 Force that a machine applies to an object
Term
 Work input
Definition
 Work put into a machine
Term
 Work output
Definition
 Work exerted by a machine
Term
 W = F x d
Definition
 Work formula
Term
 Ideal machine
Definition
 Theoretical machine in which work output is equal to work input due to no friction
Term
Definition
 The number of times a machine multiplies the effort force applied to it
Term
 MA = Fr / Fe
Definition
 Mechanical advantage formula for any machine
Term
 greater than 1
Definition
 Machines that multiply the force applied to them have a mechanical advantage that is ____.
Term
 equal to 1
Definition
 Machines that only change the direction of the effort force have a mechanical advantage that is ___.
Term
 less than 1
Definition
 Machines that only change the direction of an applied force or the speed at which it moves have a mechanical advantage that is ___.
Term
 Simple machines
Definition
 Machines that make work easier with just one movement
Term
 Lever
Definition
 A bar that is free to pivot around a fixed point
Term
 Fulcrum
Definition
 The point around which a lever rotates
Term
 IMA = Le/Lr
Definition
 Formula for IMA of a lever
Term
 First-class lever
Definition
 Lever where fulcrum is positioned between the effort and resistance forces
Term
 Second-class lever
Definition
 Lever where resistance force is positioned between the fulcrum and effort force
Term
 Third-class lever
Definition
 Lever where effort force is positioned between the resistance force and fulcrum
Term
 Pulley
Definition
 Modified lever where a chain or rope runs through a grooved wheel
Term
 1
Definition
 IMA of a single fixed pulley is ___.
Term
 2
Definition
 IMA of a single movable pulley is ___.
Term
 Block and Tackle
Definition
 A system of multiple pulleys
Term
 number of ropes supporting the resistance force
Definition
 To calculate the IMA of a multiple pulley system, simple count the ____.
Term
 Wheel and axle
Definition
 A modified lever in which two wheels of different sizes rotate together.
Term
 Wheel
Definition
 The effort force is applied to the ____ of a wheel and axle
Term
 Axle
Definition
 The ___ of a wheel and axle applies the resistance force and is smaller in diameter.
Term
 IMA = rw/ra
Definition
 Formula for calculating the IMA of a wheel and axle
Term
 Gear
Definition
 A wheel and axle with teeth
Term
 Inclined plane
Definition
 Type of simple machine with a sloping surface used to raise objects
Term
 IMA = length/height
Definition
 IMA formula for an inclined plane
Term
 Screw
Definition
 An inclined plane that is wound in a spiral around a cylindrical post
Term
 Wedge
Definition
 An inclined plane with one or more sloping sides that moves through a material to separate it
Term
 Levers, pulleys, wheel and axles     Inclined plane, screw, wedge
Definition
 Classify the six simple machines into two groups of related machines
Term
 Compound machine
Definition
 A machine that is a combination of two or more simple machines
Term
 Efficiency
Definition
 Measures how much of the work put into a machine is changed to useful work put out of the machine
Term
 Wout/Win x 100
Definition
 Efficiency formula
Term
 Power
Definition
 Rate at which work is done
Term
 P = W/t
Definition
 Power formula
Term
 watt
Definition
 Power is measured in _____.
Term
 1 Joule/second     kilowatt
Definition
 1 watt is equal to _____.   1000 watts is a _____.
Term
 heat
Definition
 Friction changes the useful work of a machine into ___ energy.
Term
 less
Definition
 When a machine is used to perform a task, the  work output is always ____ than the work input.
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